Chronic nonspecific respiratory disease in Berlin, New Hampshire, 1967 to 1973. A further follow-up study.

The 1967 sample of Berlin, New Hampshire was resurveyed in 1973 by means of a standard questionnaire on respiratory symptoms and by simple tests of pulmonary function. Measurements of the levels of air pollution showed a decrease in the number of suspended particulates and an increase in the concentration of sulfation. These values were close to the Federal Primary Standard. No differences in respiratory symptoms, prevalences of chronic, nonspecific respiratory disease, or pulmonary function were detected. Within the limitations of this study, we concluded that the Federal Primary Standards for sulfur dioxide and total suspended particulates are probably adequate to protect the public.